Power assisted feed for a kelly bar



June 18, 1963 R. J. WOOLGAR 3,094,312

POWER ASSISTED FEED FOR A KELLY BAR Filed Feb. 29. 1960 5 sneaks-sheet 1 June 18, 1963 R. J. WOOLGAR POWER ASSISTED FEED FOR A KELLY BAR 5 Sheets-Sheet 2 Filed Feb. 29, 1960 June 18, 1963 R. J. WOOLGAR 3,

POWER ASSISTED FEED FOR A KELLY BAR Filed Feb. 29, 1960 5 Sheets-Sheet 3 -30 s2 Fig.4. 2s 14 17; 4\ e IIIIIIIIIIIIII I g I I I l 1 {iii 1 June 18, 1963 Filed Feb. 29. 1960 R. J. WOOLGAR POWER ASSISTED FEED FOR A KELLY BAR 5 Sheets-Sheet 4 June 18, 1963 R. J. WOOLGAR 3,094,312

POWER ASVSISTED FEED FOR A KELLY BAR Filed Feb. 29, 1960 3 5 Sheets-Sheet 5 4o wjjgi ugig jjjj:11: I 43 4Q :1 i I I57 Eg.6. 48 y ET... I 52 54 53 44 53% i2 r 1 1 l I 1 I imp United States Patent 3,094,312 POWER ASSISTED FEED FOR A KEL LY BAR Reginald John Woolgar, Hayes, England, assrgnor to liconomics Foundations Limited, Hayes, England, a British company Filed Feb. 29, 1960, Ser. No. 11,546 Claims priority, application Great Britain June 17, 1959 2 Claims. (Cl. 25429) The present invention relates to earth drilling equipment of the kind in which a generally vertical drilling anger or like tool is attached to the lower end of a ver tically suspended kelly bar of non-circular cross-section, the auger being rotated by rotation of a non-circular guide through which the kelly bar passes. In such equipment the downward force exerted on the anger is usually that of the Weight of the kelly bar, but in some cases it: is desirable that additional downward thrust should be imparted.

It is an object of the present invention to provide a power-assisted feed for a kelly bar which enables such additional thrust to be imparted.

According to the present invention there is provided a power-assisted feed for a kelly-bar comprising a rotatable member having a central opening for the axial passage therethrough of a generally vertical kelly bar, at least two gripping members operatively associated with the rotatable member and symmetrically disposed about the central opening therein and adapted to cooperate in releasably gripping the sides of the kelly bar and thrust means adapted to apply axial thrust to the rotatable member whereby downward thrust can be transmitted to the kelly bar.

The rotatable member is preferably constituted by an inner ring rotatably mounted within a coaxial outer ring, the thrust means being operative on the outer ring and the thrust being transmitted to the rotatable ring through the mounting.

The thrust means should be capable of exerting a downward thrust on the rotatable member, and may for example include a fluid-pressure ram, the piston of which may be connected to an outer ring whence the thrust is transmitted by way of the rotatable mounting to the rotatable ring.

The rotatable member is preferably provided with structure defining a coaxial non-circular second opening to closely surround a kelly bar of corresponding noncircular section, whereby the rotation of the member is effected without undue lateral stress on the gripping members.

In the feed according to the invention the gripping members comprise at least two toggle members symmetrically disposed about the central opening, and the feed further includes toggle-locating means for locating the mutually remote edges of the toggle members loosely at or near the edge of the central opening, the mutually proximate edges of the toggle members being formed to cooperate in gripping the sides of the kelly bar when the said proximate edges are all displaced below the plane of the said remote edges, and toggle engagement means for urging the proximate edges of the toggle members upwards so as to engage the kelly bar, whereby the kelly bar can be gripped between the proximate edges of the toggle members when the rotatable ring is moved downwards, and can be released when the ring is moved upwards.

The toggle-locating means are conveniently constituted by recesses formed at the edge of the central opening and adapted to accommodate and support the rearrnost portions of the toggle members.

The toggle members may take the form of plates havof the lower flange 21,

3,094,312 Patented June 18, 1963 ing cut-outs in their mutually proximate edges which cooperate to form a non-circular opening to closely surround a kelly bar of corresponding non-circular section. Thus, for use with a kelly bar of square cross-section, two toggle plates may be provided having opposed proximate edges with opposed rectangular cut-outs which cooperate to form a square opening when the said proximate edges are displaced below the plane of the remote edges of the plates.

As the kelly bar is gripped by the toggle members when the rotatable ring is moved downwards, so the toggle members will tend to become locked on the bar if it is raised through the ring. As it is normally necessary to raise the kelly bar, for example in withdrawing a drilling tool from a boring, the feed according to the invention is provided with means to automatically release the rising kelly from the grip of the toggle members. Such means may operate by limiting the upward movement of the proximate edges of the toggle members when the whole toggle and ring assembly is raised by the rising kelly bar. The proximate edges will thus be depressed relative to the ring and thus relative the remote edges, and their grip on the rising kelly is thereby released. Upward movement of the ring occasioned by the movement of the kelly bar is thus arrested.

One embodiment of the invention will now be described by way of example. In the embodiment described the power-assisted feed is mounted above the rotary drive provided for the rotation of the kelly bar. Reference wiil be made to the accompanying drawings in which:

FIG. 1 is a side elevation of a first embodiment of the inxention with a kelly bar in position,

FIG. 2. is an end elevation of the embodiment shown in FIG. 1,

FIG. 3 is a top plan view of the same embodiment,

FIG. 4 is a vertical section of the same embodiment, taken along the line IV-IV in FIG. 3,

FIG. 5 is a horizontal cross-section of the same embodiment, partly cut away, taken along the line VV in FIG. 4.

In the embodiment shown in FIGS. 1-5 the gripping members are constituted by toggle plates, and the feed is mounted above the rotary drive for the kelly bar.

On the casing 10 of the rotary drive are vertically mounted the cylinders 11 of two hydraulic rams. The upper ends of the piston rods 12 carry links 13 the ends of which are welded to opposite sides of a horizontal steel outer ring 14. The inner face of the outer ring is furnished with four equally spaced, inwardly directed, Phosphor bronze slippers 15. A rotatable steel inner ring 16, coplanar and coaxial with the outer ring, has around its outer edge a continuous uniform groove in which are engaged the Phosphor bronze slippers 15, the inner ring thus being rotatably mounted Within the outer. The upper face of the rotatable inner ring 16 is constituted by an upper plate 17 having at its centre a square opening through which a kelly-bar 18 of corresponding cross-section can pass. The lower face of the rotatable ring is constituted by a lower flange 21 which has a large octagonal opening at its centre and which is joined to but spaced from the upper plate by an annular portion 22.

The inner surface of the annular portion 22 is generally octagonal in plan, and is set back from the inner edge thereby forming at opposite sides of the ring two straight recesses 23. The inner, upper angles of these recesses, that is the angles between the annular portion 22 and the overhanging upper plate 17, may be radiused to provide smooth bearing surfaces for the remote edges of the two toggle plates 24. The recesses may contain members 25 to provide the bearing surfaces. The toggle plates 24 are heavy steel plates of generally trapezoidal plan, the remote edge 26 of which lie within the recesses 23 at the sides of the rotatable ring.

The mutually proximate edges 27 of the toggle plates are closely opposed, and are provided with rectangular cut-outs which can form a square to closely surround a kelly bar 18 of corresponding cross-section. The dimensions of the plates 24, and in particular the depth of the plates from proximate to remote edges, are such that this square is formed only when the proximate edges are appreciably displaced below the plane of the recesses 23. The plates can therefore combine to exert a toggle gripping action on a kelly bar passing through the square hole between them.

The upper plate 17 is provided with two holes situated on the diameter parallel to the proximate edges 27 of the plates 24 and at points on that diameter above the ends of the proximate edges. Through these holes pass two long adjusting bolts 30 having their heads uppermost, and each being furnished with a nut 31 disposed above the upper plate 17 and spaced therefrom by a helical compression spring 32, the feet of the two springs surrounding the respective holes in the upper plate. To the lower end of each bolt is fixed a pair of vertically spaced horizontal small plates 33 and 34, each pair embracing the corresponding ends of the proximate edges of the two toggle plates 24. Thus the proximate edges 27 of the two toggle plates are urged upwards by the lower small plates 33 of each pair and the toggle plates are thereby retained within the rotatable ring 16 in the absence of a kelly bar, or are urged into light contact with a kelly bar 18 in position in the feed. This allows the kelly bar to be fed downwards freely through the device, and without power assistance if so desired.

The nut 31 above the spring 32 permits initial adjust- Q ment of the small horizontal plates 33 and 34 to bring the toggle plates 24 into suitable light contact with the kelly bar 18.

On the upper side of the casing of the rotary drive is mounted a fixed superstructure 35 of which a top plate 36 passes above the two adjusting bolts 30 in positions in which the heads of the bolts can come into contact with the underside of the top plate, usually when the ram pistons 12 are nearly at the top of their stroke. Further upward movement of the ram pistons will result in a depression of the two bolts 30 relative to the upper plate 17 of the rotatable ring 16, against the spring pressure, and hence relative lowering of the proximate edges 27 of the toggle plates 24. The top plate may itself be adjustable for height by means of adjustable bolts 37 on the superstructure, so that the point of release of the toggle plates from the kelly bar can be set to any desired position within the stroke of the rams. Anti-torque guides 37 may be provided to restrain rotary movement of the outer ring 14 relative to the superstructure, thereby relieving the rams of undue lateral stress which might result from friction in the rotatable mounting of the inner ring 16.

in operation, when a kelly bar 18 is in position in the feed, and has been lowered with a drilling tool attached to its lower end into a bore hole, the ram pistons 12 which have previously been at the upper reach of their stroke are caused to move downwards, carrying the outer ring 14 and the rotatable ring 16 with them. The proximate edges 27 of the two toggle plates 24, being already held against the kelly bar 18 by the operation of the compression spring 32, exert a toggle gripping action on the sides of the kelly bar and transmit to it the downward thrust of the rams. When the rams reach the bottom of their stroke, they can be returned to the top of their stroke, the toggle plates 24 sliding upwards along the kelly bar. The rams can thereupon be lowered again and an unlimited length of kelly bar can thus be passed step by step through the feed, if so required.

When drilling is completed and the kelly bar is to be removed from the bore-hole, the kelly bar 18 is raised by a hoist attached to its upper end and, with the rams set to move upwards, the toggle plates 24 become locked about the kelly bar and carry the rings 14 and 16 and ram pistons 12 upwards. At the upper part of the stroke of the rams, the heads of the adjusting bolts 30 come into contact with the underside of the top plate 36 of the superstructure 35. The bolts are thereby depressed relative to the rings 14 and 16, against the action of the compression springs 32, until the upper small plates 34 of each pair come into contact with the ends of the proximate edges 27 of the toggle plates 24, whereupon the proximate edges are forced away from the sides of the kelly bar 18, which can thus be hoisted freely to any desired height.

I claim:

1. A power-assisted feed for a kelly bar comprising a frame structure, at least one fluid-pressure ram mounted on said frame structure and including a movable member, said ram being adapted to exert a downward thrust, thrust bearing means carried by the movable member of said fluid-pressure ram, a rotatable member rotatably supported by said thrust bearing means and having an axial opening adapted for the passage therethrough of a vertical kelly bar, at least two toggle members symmetrically disposed about the central opening and having mutually remote edges loosely supported in the rotatable member and mutually proximate edges formed to cooperate in gripping the kelly bar when the toggle members are downwardly inclined and downward thrust is applied to the rams, resilient means, toggle engagement means carried in vertically movable manner on said rotatable member and upwardly biased by said resilient means, and having a first abutment surface arranged to engage said toggle members to lift the proximate edges of said toggle members into contact with said kelly bar when said ram is displaced from the top of its stroke, and a second abutment surface arranged to engage said toggle members, and a stop member mounted on said frame structure where it can be engaged by said toggle engagement means when said ram is substantially at the top of its stroke to depress said toggle engagement means against the action of said resilient means to cause said second abutment surface to engage and depress said toggle members.

2. A power-assisted feed according to claim 1 wherein the toggle members have the form of plates having cut-outs in their mutually proximate edges which form in conjunction with one another a non-circular opening adapted to surround closely a kelly bar of corresponding non-circular section.

References Cited in the file of this patent UNITED STATES PATENTS 2,126,933 Stone et al. Aug. 16, 1938 2,310,960 Johansen Feb. 16, 1943 2,393,603 Beeth Jan. 29, 1946 2,638,324 Ball et al. May 12, 1953 2,730,331 Harinick Jan. 10, 1956 FOREIGN PATENTS 419,187 Germany Sept. 21. 1925 

1. A POWER-ASSISTED FEED FOR A KELLY BAR COMPRISING A FRAME STRUCTURE, AT LEAST ONE FLUID-PRESSURE RAM MOUNTED ON SAID FRAME STRUCTURE AND INCLUDING A MOVABLE MEMBER, SAID RAM BEING ADAPTED TO EXERT A DOWNWARD THRUST, THRUST BEARING MEANS CARRIED BY THE MOVABLE MEMBER OF SAID FLUID-PRESSURE RAM, A ROTATABLE MEMBER ROTATABLY SUPPORTED BY SAID THRUST BEARING MEANS AND HAVING AN AXIAL OPENING ADAPTED FOR THE PASSAGE THERETHROUGH OF A VERTICAL KELLY BAR, AT LEAST TWO TOGGLE MEMBERS SYMMETRICALLY DISPOSED ABOUT THE CENTRAL OPENING AND HAVING MUTUALLY REMOTE EDGES LOOSELY SUPPORTED IN THE ROTATABLE MEMBER AND MUTUALLY PROXIMATE EDGES FORMED TO COOPERATE IN GRIPPING THE KELLY BAR WHEN THE TOGGLE MEMBERS ARE DOWNWARDLY INCLINED AND DOWNWARD THRUST IS APPLIED TO THE RAMS, RESILIENT MEANS, TOGGLE ENGAGEMENT MEANS CARRIED IN VERTICALLY MOVABLE MANNER ON SAID ROTATABLE MEMBER AND UPWARDLY BIASED BY SAID RESILIENT MEANS, AND HAVING A FIRST ABUTMENT SURFACE ARRANGED TO ENGAGE SAID TOGGLE MEMBERS TO LIFT THE PROXIMATE EDGES OF SAID TOGGLE MEMBERS INTO CONTACT WITH SAID KELLY BAR WHEN SAID RAM IS DISPLACED FROM THE TOP OF ITS STROKE, AND A SECOND ABUTMENT SURFACE ARRANGED TO ENGAGE SAID TOGGLE MEMBERS, AND A STOP MEMBER MOUNTED ON SAID FRAME STRUCTURE WHERE IT CAN BE ENGAGED BY SAID TOGGLE ENGAGEMENT MEANS WHEN SAID RAM IS SUBSTANTIALLY AT THE TOP OF ITS STROKE TO DEPRESS SAID TOGGLE ENGAGEMENT MEANS AGAINST THE ACTION OF SAID RESILIENT MEANS TO CAUSE SAID SECOND ABUTMENT SURFACE TO ENGAGE AND DEPRESS SAID TOGGLE MEMBERS. 